The problem is worse in households that have to travel long distances for water or lack water and soap to wash their hands. But even adequate sanitation does not offset the risk of drought-related diarrhea.
“You cannot completely eliminate the impact of drought on diarrhea risk, especially in a climate where there will be more droughts in the future,” said Kai Chen, PhD, an assistant professor. in the Department of Epidemiology (Environmental Health) at the Yale School of Public Health. and a senior author of the study. “We need to reduce greenhouse gas emissions.”
This study is the largest to date to investigate the impact of prolonged drought on diarrhea risk in children living in low- and middle-income countries (LMICs). It is also the first of its kind to use a new drought measure that takes into account both water supply and demand.
Diarrhea can arise from contact with contaminated food or water, animal feces, or another infected person. Although the relationship between rainfall and diarrhea has been extensively studied, evidence linking drought and diarrhea is scarce.
Young children are most at risk
To better understand the relationship between drought and diarrhea, the authors looked at international health surveys and climate data. Drought is measured at a resolution of 10 square kilometers with a metric known as the standardized precipitation evapotranspiration index (SPEI).
Data on recent episodes of diarrhea were collected between 1990 and 2019 by the Demographic and Health Survey, a partnership between USAID and dozens of countries around the world. The surveys collected information on more than 1.3 million children under the age of five living in 51 countries in sub-Saharan Africa, South and Southeast Asia, Latin America and the Caribbean.
Across all countries surveyed, 14.4% of children had diarrhea in the past 2 weeks. The risk is highest in children between 6 and 23 months.
In Niger, the worst-affected country, about 36.4% of children have recently fallen ill. Other hard-hit countries include Bolivia, Liberia, Central African Republic, Burundi, Malawi and Haiti, where about a fifth of children were recently affected.
Living in dry conditions for six months increases the risk of diarrhea by 5% if the drought is mild, or 8% if the drought is severe. Access to good water, sanitation and hygiene (WASH) facilities, such as adequate soap and water, provides low to moderate protection from the risk of diarrhea.
At the same time, children in households that take a long time to get water — more than half an hour — or in places where soap and water are not available to wash their hands, are at greater risk.
Number of deaths due to diarrhea
Children who survive diarrhea may have impaired growth and development and are more susceptible to chronic illness. But many others did not survive.
Those statistics are likely to worsen as climate change is expected to make droughts worse and longer lasting.
Drought can increase concentrations of dangerous bacteria and viruses in water supplies. In addition, when water is scarce, drinking water is preferred over use for personal hygiene. For many people at LMIC, it can take hours of travel to access water.
Diarrhea prevention calls for simple measures such as access to safe drinking water and sanitation facilities.
But it is not possible to completely eliminate the number of drought-related diarrheal diseases.
“International collaborative efforts are needed to improve WASH infrastructure, especially in these low-resource communities. For these children, it certainly helps,” said Chen, who is also Research Director of the Medical Center for Climate Change and Health at Yale. Yale School of Public Health. “But washing your hands isn’t enough to protect you. We need to address the root causes of climate change.”